1. Field of the Invention
The present invention relates generally to media content protection, in particular to protection against signal duplication in media playback devices.
2. Description of Related Art
Content rights management relates to the management of the rights to own or use the content in the form of books, tapes, TV or radio broadcasting, and other information expression. In particular, the management method controls the usage rights in respect to the frequency and duration to view, copy, loan, edit, print, exchange and transfer.
In this computer age, content rights management is more emphasized in copyright protection in the area of digital media than that of the analog media. There are two reasons regarding the static and dynamic aspects. Firstly, digital content may exist as an archive (static), which can be easily copied or duplicated to give the original quality of media content. Secondly, digital content can be easily distributed (dynamic) in the fast and convenient Internet connection.
As for analog format media content, the case is totally different. It has to be carried in an analog physical media such as tape for audio/video, paper for text/photo, etc. When the content is to be copied and distributed, such analog content requires time-consuming and high cost methods to retain original quality of media content and hence discourage piracy issues.
Therefore, there exist prior art to protect and prevent digital audio media from ripping in personal computer to stop music piracy. The methods include incorporating protection in CD, DVD, and encrypting the compressed audio content therein.
The on-line music subscription is becoming popular and successful, for example, in the case of Apple's iPod, where it has over one million songs per month downloaded from its iTune web site. This implies that the on-line music subscription business model would create new music distribution channels, in contrast with the conventional compact discs in retail shops, and the consumer is prepared to accept the same.
Currently, there are five essential parties to construct an on-line music subscription business, namely the content provider, distributor, retailer, playback device manufacturer, and music consumer. The content provider is a music publisher (BMG, Sony, Warner, Universal, etc), that relies heavily on the distributor (Apple, Microsoft, Napster, Sony, Intel, Yahoo, Google, etc.) to provide content protection, security, rights management and distribution infrastructure services.
The retailers are the Internet portals (Yahoo, Google, MSN etc.) and shopping web sites (Amazon, Wal-Mart, iTune, Napster, Microsoft, etc.). The playback device manufacturer (Philips, Samsung, Creative, JNC, etc) produces compliance devices according to the distributor's requirement to implement the rights management, security and protection scheme. Finally, the music consumer subscribes to the music download service, and they may also join subscription plans to get a free or discounted media player, mp3 player or mobile phone, etc. for playback of the media content.
The distributor provides very intensive security and protection to block direct digital copy. Despite these intended measures, some current analog ripping and audio recording devices can duplicate very high quality media content by re-sampling at the analog output of playback devices (such as at the connector output for headphones or speakers). The dubbed data can be converted into a digital signal providing comparable quality as the original content. After that, it can easily be transformed into different digital formats such as mp3, WMA, etc. and distributed over the Internet, resulting in piracy problems. There is no current feasible solution to stop or discourage such analog rip-off from the audio output connector.
Thus, this analog loophole has become the Achilles' heel of Digital Rights Management (DRM) technology. Accordingly, a need yet exists for improved methods and apparatuses that protect media content against duplication at the media playback stage.